1. Field of the Invention
This invention relates to propulsion systems. Specifically, and not by way of limitation, the present invention relates to a system and method of propelling a space elevator using mechanical waves.
2. Description of the Related Art
There have been many benefits which we have enjoyed because of space travel. For example, communication systems involving telecommunications and broadcasting rely on a series of orbiting satellites. Satellites are also used for surveying and surveillance of various regions of the world. There is currently an international space station housing a few astronauts and cosmonauts for extended periods of time. However, a prime obstacle to further utilization of space orbiting systems is the cost of launching objects and humans into space. Costly rockets are needed to propel vehicles into space. Because of these costs, these space based orbiting systems are used in manner less than desired.
One alternative to launching rockets into space is the utilization of a space elevator. A space elevator has been proposed which can transport material from a celestial body's surface (i.e., the Earth) into space. Many variants have been proposed, all of which involve traveling along a fixed structure, instead of using rocket powered space launch. The concept most often refers to a structure that reaches from the surface of the Earth on or near the Equator to geostationary orbit (GSO) and a counter-mass beyond.
FIG. 1 is a simplified side view of a space elevator. A cable 10 is affixed to the surface of the Earth 12. The cable extends out into space and ends in a counterweight 14 orbiting the Earth. Inertia ensures that the cable remains stretched taut, countering the gravitational pull on the lower sections, thus allowing an elevator system 16 to remain in geostationary orbit. A carriage 18 carrying passengers and/or cargo would run upon the cable to reach orbit. Once beyond the gravitational midpoint, the carriage would be accelerated further by the planet's rotation.
The use of a space elevator shows great promise. However, there are various technological obstacles. A primary obstacle is finding a mechanism to propel the carriage to space. The mechanical lifting power, P, is equal to the weight of the carriage, mg, multiplied by the vertical velocity, v, of travel. Therefore: P=mgv. A reasonable value for v is 33 meters/sec. Thus, P=(10 000 kg)(9.8 meters/sec/sec)(33 meters/sec)=3.234 million Watts. Therefore, in order to propel a 10,000 kilogram carriage into space, over 3 million Watts of power need to be transmitted to the carriage. A primary proposal for propelling the carriage on the cable is a laser/optical conversion system. The laser/optical system depends on having clear weather, which does not always occur and suffers from the problem of conversion efficiency. Proponents of the laser/optical system expect to solve the weather problem by anchoring the space elevator cable on a ship at sea, which can then be maneuvered over several hundred miles. However, for various reasons, it would be far more beneficial to build a space elevator that is anchored to land.
Thus, it would be advantageous to have a land based propulsion system which efficiently propels a carriage up into space. It is an object of the present invention to provide such a system.